Fix spawn EINVAL error on Windows (#84)

Fixes #83

index.js

@@ -1,5 +1,4 @@
 var proc = require('child_process')
-var execspawn = require('execspawn')
 var os = require('os')
 var path = require('path')
 var fs = require('fs')
@@ -179,11 +178,12 @@ function copySharedLibs (builds, folder, opts, cb) {
 function run (cmd, opts, cb) {
   if (!cmd) return cb()
 
-  var child = execspawn(cmd, {
+  var child = proc.spawn(cmd, [], {
     cwd: opts.cwd,
     env: opts.env,
     stdio: 'inherit',
-    shell: opts.shell
+    shell: opts.shell || true,
+    windowsHide: true
   })
 
   child.on('exit', function (code) {
@@ -230,6 +230,8 @@ function build (target, runtime, opts, cb) {
     var child = proc.spawn(opts.nodeGyp, args, {
       cwd: opts.cwd,
       env: opts.env,
+      shell: opts.shell,
+      windowsHide: true,
       stdio: opts.quiet ? 'ignore' : 'inherit'
     })
 
@@ -266,7 +268,11 @@ function strip (file, opts, cb) {
   if (!opts.strip || (platform !== 'darwin' && platform !== 'linux')) return cb()
 
   var args = platform === 'darwin' ? [file, '-Sx'] : [file, '--strip-all']
-  var child = proc.spawn(opts.stripBin, args, { stdio: 'ignore' })
+  var child = proc.spawn(opts.stripBin, args, {
+    stdio: 'ignore',
+    shell: opts.shell,
+    windowsHide: true
+  })
 
   child.on('exit', function (code) {
     if (code) return cb(spawnError(opts.stripBin, code))
@@ -300,7 +306,11 @@ function npmbin (name) {
 }
 
 function shell () {
-  return os.platform() === 'android' ? 'sh' : undefined
+  switch (os.platform()) {
+    case 'win32': return true
+    case 'android': return 'sh'
+    default: return undefined
+  }
 }
 
 function resolveTargets (targets, all, napi, electronCompat) {

package.json

@@ -4,11 +4,10 @@
   "description": "Create and package prebuilds for native modules",
   "main": "index.js",
   "dependencies": {
-    "execspawn": "^1.0.1",
+    "minimist": "^1.2.5",
     "mkdirp-classic": "^0.5.3",
     "node-abi": "^3.3.0",
     "npm-run-path": "^3.1.0",
-    "minimist": "^1.2.5",
     "pump": "^3.0.0",
     "tar-fs": "^2.1.0"
   },